Thank you, rneill. You raise an interesting issue. To borrow from NORSOK L-CR-004, a 2" to 10" flange face must be square with the pipe it is welded to within 1.5 mm. If the valve body was considered a very short piece of pipe, that would allow paralellism to be 3 mm. That's huge.
What "Code"...
Does anyone know of a published standard for straight-pattern valve body flange face parallelism? When flanges are welded to a butt weld glove valve body, there is no assurance of inherent parallelism as there would be if the facings were machined on a cast or forged body.
I've been to the...
Would a 5000 psi rated valve fabricated from a butt-weld body of 75K material and weld-neck flanges require the flanges to be 60K or 75K material? According to API 6A -19th edition Table 4, a flanged “Integral end connection” must by of 60K or 75K material, though butt-weld 5000 psi flanges are...
I very much appreciate all the input on this subject. Many of the responders have refered to industry standards, and I believe we have revealed that interpretation of some requirements can be difficult.
What I find interesting is that none of the responders has answered the original question...
When a custom-fabricated, unique valve makes S1 impractical, I strongly recommend proof testing and certification per the BPV Code, UG-101. This would confirm the applicability of the material type and form as accurately marked on the product.
As recommended by earlier posts, it is critical to...
The restrictions in ASTM A350 5.3.3 and A961 6.1.1 (referenced by A105) do not contstrain the detailed machining of parts. The requirements are there to assure good design practice, which is to align the direction of greatest tensile strength of the material with the principle stresses induced...
kenvlach's input causes this subject to take an interesting turn. Though ASME B16.34 does not specifically preclude the use of forged bar to make a valve body, MSS SP-25 requires that the material designation be on the body. The "criminal" act would be the false impression given by "A105" on the...
ASTM A 350/A 350 - 04a para 5.3.3 states "Except for flanges of all types, hollow, cylindrically shaped parts may be machined from rolled bar or seamless tubular materials provided that the axial length of the part is approximately parallel to the metal flow lines of the stock. Other parts...
A section of forged bar per ASTM A350 LF2 is used to make a valve body. I was told by a forging supplier that the body could not be claimed to be a forging. OK, but then if the valve body is marked "A350 LF2", would that not imply it was made from a forging, since A350 is by nature a forging...
What does this body of knowledge have about material choices for resisting erosion damage from fluids that are also corrosive? Since erosion resistance typically has an inverse relationship to corrosion resistance, would a Rc 55 low alloy steel (e.g. Nitralloy 135) suffer from corrosion to the...
The "B16.34 materials" are those allowable by the B16 committee for pressure containing parts or those directly affecting the pressure containment boundary (para 5.1). They are selected based on many factors that influence structural integerity over time.
The valve manufacturer can use whatever...
We have experienced severe erosion damage to control valve trim in demineralized water service. We've tried tungsten carbide with cobalt-, nickel-, and even a proprietary ceramic-binder.
Before I start a new thread on this subject, what is known about wear-resistance materials for surfaces...
Thanks to all those providing input. Of particular value were the recommendations of sjones and pennpiper (PFI ES-3 was only $25 through Global, and the NORSOK spec is public domain). Since we don't have a copy of the $250 TEMA standard, abeltio's reference didn't help, though it's nice to know...
Does anyone know of industry standards addressing parallelism of flange faces prior to installation? We have experienced a cracked fillet weld at the socket connection of a short lap-joint flange hub into a rigid pressure vessel. During installation, as the raised faces (piping flange and hub)...
OK. Therefore a part machined from "forging stock" could only be allowable (per B16.34) if made from, per A 350 5.3.3, "rolled bar or seamless tubular materials provided that the axial length of the part is approximately parallel to the metal flow lines of the stock." In that case it would be...
